Análise genética dá esperanças de espécies de tartarugas extintas renascerem

Source/Fonte: PhysOrg

DNA from the Past Informs Ex Situ Conservation for the Future: An “Extinct” Species of Galápagos Tortoise Identified in Captivity

Michael A. Russello^1*, Nikos Poulakakis², James P. Gibbs³,Washington Tapia⁴, Edgar Benavides⁵, Jeffrey R. Powell⁵,Adalgisa Caccone⁵

1 Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada, 2 Department of Biology and Natural History Museum of Crete, University of Crete, Irakleio, Crete, Greece, 3 College of Environmental Sciences and Forestry, State University of New York, Syracuse, New York, United States of America, 4 Galápagos National Park Service, Puerto Ayora, Galápagos, Ecuador, 5 Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America

Abstract


Background
Although not unusual to find captive relicts of species lost in the wild, rarely are presumed extinct species rediscovered outside of their native range. A recent study detected living descendents of an extinct Galápagos tortoise species (Chelonoidis elephantopus) once endemic to Floreana Island on the neighboring island of Isabela. This finding adds to the growing cryptic diversity detected among these species in the wild. There also exists a large number of Galápagos tortoises in captivity of ambiguous origin. The recently accumulated population-level haplotypic and genotypic data now available for C. elephantopus add a critical reference population to the existing database of 11 extant species for investigating the origin of captive individuals of unknown ancestry.

Methodology/Findings
We reanalyzed mitochondrial DNA control region haplotypes and microsatellite genotypes of 156 captive individuals using an expanded reference database that included all extant Galápagos tortoise species as well as the extinct species from Floreana. Nine individuals (six females and three males) exhibited strong signatures of Floreana ancestry and a high probability of assignment to C. elephantopus as detected by Bayesian assignment and clustering analyses of empirical and simulated data. One male with high assignment probability to C. elephantopus based on microsatellite genotypic data also possessed a “Floreana-like” mitochondrial DNA haplotype.

Significance
Historical DNA analysis of museum specimens has provided critical spatial and temporal components to ecological, evolutionary, taxonomic and conservation-related research, but rarely has it informed ex situ species recovery efforts. Here, the availability of population-level genotypic data from the extinct C. elephantopus enabled the identification of nine Galápagos tortoise individuals of substantial conservation value that were previously misassigned to extant species of varying conservation status. As all captive individuals of C. elephantopus ancestry currently reside at a centralized breeding facility on Santa Cruz, these findings permit breeding efforts to commence in support of the reestablishment of this extinct species to its native range.

Citation:Russello MA, Poulakakis N, Gibbs JP, Tapia W, Benavides E, et al. (2010) DNA from the Past Informs Ex Situ Conservation for the Future: An “Extinct” Species of Galápagos Tortoise Identified in Captivity. PLoS ONE 5(1): e8683. doi:10.1371/journal.pone.0008683
Editor:Michael Knapp, University of Otago, New Zealand
Received: November 11, 2009; Accepted: December 20, 2009; Published: January 13, 2010 
Copyright: © 2010 Russello et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: Funding was provided by the Paul and Bay Foundation, Turtle Conservation Fund, National Geographic Society, and Yale Institute for Biospheric Studies (YIBS) Ecosave funds to AC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.

* E-mail: michael.russello@ubc.ca

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